Memoirs of Extraordinary Popular Delusions and the Madness of Crowds

The book chronicles its subjects in three parts: "National Delusions", "Peculiar Follies", and "Philosophical Delusions". Despite its journalistic and rather sensational style, the book has gathered a body of academic support as a work of considerable importance in the history of social psychology and psychopathology.

The subjects of Mackay's debunking include economic bubbles, alchemy, crusades, witch-hunts, prophecies, fortune-telling, magnetisers (influence of imagination in curing disease), shape of hair and beard (influence of politics and religion on), murder through poisoning, haunted houses, popular follies of great cities, popular admiration of great thieves, duels, and relics.